Portable crane



April 27, 1937. R. G. LE TOURNEAU 2,078,393

PORTABLE CRANE Filed Oct. 15, 1955 2 Sheets-Sheet 1 I\ N N N 3' INVENTORl 4 R. G.LeT0Lu'12eaw April 27, 1937'. R, G, LE TOURNEAU 2,078,393

PORTABLE CRANE Filed Oct. 15, 1935 2 Sheets-Sheet 2 INVENTORRGLBTOuI'Heau Patented Apr. 27, 1937 PATENT OFFICE ron'ranm cam Robert0. Le Tonrnean, swims, aasignor. to B. GrLe Tournean, Ino., Stockton,Calif.,,a

corporation Application October 15, 1935, Serial No. 45,040

Claims.

This invention relates to portable wheel mounted cranes adapted to beconnected to and operated from a tractor, my principal object being toprovide an apparatus of thistype having great lifting capacity for itssize, and great flexibility of operation, and which can be used forgeneral utility purposes by construction engineers, contractors andothers, as for'instance to load and unload heavy equipment, handle largeconcrete or steel pipe, place heavy members in bridge construction, setmachinery, move heavy equipment for repairs or other purposes, and forinnumerable other duties.

A further object of the invention is to produce a simple and inexpensivedevice and yet one which will be exceedingly effective for the purposefor which it is designed.

These objects I accomplish by means of such structure and relativearrangement of parts as will fully appear by a perusal of the followingspecification and claims.

In the drawings similar characters of reference indicate correspondingparts in the several views: Figure 1 is a side elevation of my improved25 crane as attached to a tractor.

Figure 2 is a rear end view of the crane with the cables removed.

Referring now more particularly to the char acters of reference on thedrawings, the crane 30 comprises a relatively long rigid tongue Iadapted wheels 8 are turnable. The above parts form the supporting baseor vehicle of the crane.

The boom of the crane comprises transversely 0 spaced upwardlyconverging arms 9 braced in a transverse plane by suitable members I0and in a longitudinal plane by a truss structure I I. The arms at theirupper end are bent rearwardly so as to provide rearwardly overhangingportions 45 I! when the boom is in a vertical position as indicated indotted lines in Figure 1. To keep the boom from tipping forwardly fromsuch vertical position I provide a pad l3 disposed some distanceahead ofthe boom to then rest on the tongue; said pad being rigidly connected tothe boom at spaced points in its length by suitable laterally divergingarms l4.

Plates I! are rigidly secured to and depend 55 from the lower ends ofthe arms 9, these plates projecting between the bosses B and the wheelsand turnably engaging and supported by the adjacent portions of thespindles 'I.

A sheave block it is rigidly fixed between the upper rear en'ds of thearms 9, and another sheave block i1 is similarly fixed in connectionwith the truss structure II at its upper peak ahead of the block it. Acable l8 extends from one drum of a power unit IS on the tractor (thisunit being preferably as shown in my Patent No. 1,912,645, dated June 6,1933) over and between certain pulleys of the blocks I! and I8, and overthose of the hook or lifting block which is disposed below and invertical alinement with the block IS. The winding of this cable on itsdrum of course raises the block l9 and any load supported thereby, andvice versa.

Another cable 2| extends from the other drum of the power unit and thenover another pulley of the block I1, and then back and forth betweensaid block and an anchor sheave block 22 flexibly mounted on the tongueadjacent its forward end. This cable is the boom controlling line and isarranged so that when the cable is wound on the corresponding drum, theboom itself will be raised about the wheel spindles as an aids.

A crane as above constructed has great lifting capacity and can handleheavy loads with safety. For example, a crane having a substantially30-foot boom and a 20-foot tongue, from the center of the wheels to thepoint of connection with the drawbar, and connected to a tractor ofaverage weight, can lift five tons when the lifting block is disposed 16feet rearwardly of the wheel center, and from there up to twelve tonswhen the said lifting block is 7 feet from the wheel center.

The reason such loads can be thus lifted is on account of the fact thatthe load is carried on the wheels and the tractor simply acts as acounterbalance. With the main weight of the tractor substantially 25feet away from the point at which the load is concentrated, it willreadily be seen, following the principle of leverage, that when the loadis swung 12 feet into space, the crane will be capable of lifting twiceas much weight as the tractor (disregarding the weight of the boom),since the tractor is twice as far away from the wheels as the load is.

While when in use the crane is connected to a tractor, its wheels may beequipped with rubber tires if desired, so that it may be towed by atractor from one place to another. The relatively great length of thetongue gives the tractor operator perfect maneuvering control, allowinghim to move in a straight line back and forth or cramp around sidewaysso as to spot his load within a fraction of an inch. The generalconstruction or form of the boom, with its rearward-' 1y overhangingportion at the top, and the fact that it may be positively held in avertical position, enables the crane to be very effectively used forbreaking up concrete or the like with a skull cracker; or by theaddition of suitable guides the crane may be used as an efficient piledriver.

When making connection with a tractor the cables are first attached tothe drums of the power unit, the boom at the time resting on the groundrearwardly of the tongue. The operator then reels in on the boom line.The boom being heavier than the tongue raises the latter of! the groundso that the drawbar may be easily engaged with the front end of thetongue and the drawbar pin inserted in place. The boom may then befurther raised to any desired angle. In disconnecting the crane from thetractor it is not necessary to block the wheels; the operator simplyreleasing the boom line so as to cause the boom to lie flat on theground, and then pulling the drawbar pin. This ease of connecting anddisconnecting the crane from the tractor makes it unnecessary to have atractor for use only with the crane, when the crane is being used butintermittently. An average of ten minutes is all that is necessary toattach and put the crane in operation, and a similar short period oftime is all that 'is required for disconnecting purposes.

From the foregoing description it will be readily seen that I haveproduced such a device as substantially fulfills the objects of theinvention as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of the device, still in practice such deviations from suchdetail may be resorted to as do not form a departure from the spirit ofthe invention, as defined by the appended claims.

Having thus described my invention, what I claim as 'new and useful anddesire to secure by Letters Patent is:

1. In combination with a tractor, a crane comprising a relatively longtongue swivelly mounted on and supported at its front end by thetractor, wheels supporting the tongue at its rear end, and a boompivoted in connection with the tongue .axially of the. wheels forswinging movement relative to the tongue.

2. In combination with a tractor, a crane comprising a relatively longtongue swivelly mounted on and supported at its front end by thetractor, transversely spaced wheels to the sides of the tongue at itsrear end, wheel spindles mounted in connection with the tongue, and aboom comprising transversely spaced arms having elements at their lowerends turnably engaging the spindles.

3. A crane comprising a tongue adapted at its front end for supportingconnection with a vehicle, wheels supporting the tongue at its rear end,and a boom supported for swinging movement about the axis of the wheels.

4. A portable crane comprising a base having a forwardly projectingtongue adapted at itsforward end for attachment to the drawbar of atractor, wheels supporting the base at its rear end, and an upstandingswinging boom pivotally mounted on the base axially of the wheels.

5. A crane comprising a base adapted at its front end for supportingconnection with a vehicle, wheels supporting the base at its rear end, aboom supported for swinging movement about the axis of the wheels, saidboom extending straight up from its lower end to a point short of itsupper end and being then deflected to provide a rear overhang, a loadengaging element depending from the rear end of the overhang and meansto raise the boom to dispose the straight portion thereof vertically;whereby the weight of a load supported by the element will then betransmittedto the base substantially at the axis of the wheels.

ROBERT G. LE TOURNEAU.

